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To save the phenomena constructive empiricism


									To save the phenomena:
constructive empiricism

    [The] belief involved in accepting a scientific
    theory is only that it ‘saves the phenomena’, that is
    that it correctly describes what is observable
                                   (van Fraassen,185-186)

    Term paper and final exam

   Final exam is scheduled for Thursday April 19, 6 pm
    in SBE 1220
   Term paper is due March 22nd. Hard copy to me and
    electronic copy to Note the proviso in
    penalty for late submissions however
   Please set up your account at and
    familiarize yourself with the site before the due date.
   Remember you are presenting an argument in
    support of a conclusion in your paper. You cannot
    just string together quotes!
     Steps leading to constructive empiricism

     What is the argument used by anti-realists to motivate our
      acceptance of their position?
     Strong underdetermination
1)    For every theory there exist an infinite number of strongly
      empirically equivalent but incompatible rival theories
2)    If two theories are strongly empirically equivalent then they
      are evidentially equivalent
3)    No evidence can ever support a unique theory more than its
      strongly empirically equivalent rivals
4)    Therefore, theory-choice is radically underdetermnined.

Steps leading to constructive empiricism

   Focus on the second premise: If two theories are
    strongly empirically equivalent then they are
    evidentially equivalent
   Distinguish between empirical and evidential
   Theory choice involves non-empirical features.
    E.g. Kinetic theory of motion

Steps leading to constructive empiricism

   What is the constructive empiricist’s response to
    the challenge?
   The underdetermination is resolved by pragmatic
    considerations, not epistemological ones

The difference between Scientific realism
and Constructive Empiricism
   Scientific realism:            Constructive empiricism:
    “science aims to give us        “science aims to give us
    … a literally true story        theories which are
    of what the world is            empirically adequate, and
    like; and acceptance of a       acceptance of a theory
    scientific theory               involves … belief only
    involves the belief that        that it is empirically
    it is true” (van Fraassen       adequate” (ibid)
    cited on 185)

    Difference between scientific realism and
    constructive empiricism
   The realist thinks             The constructive empiricist
    science aims at truth           thinks that science aims to
    with respect to                 tell the truth about what is
    unobservable processes          observable and rejects the
    and entities that explain       demand for explanation for
    observable phenomena            all regularities in what we
                                    observe; they are agnostic
                                    with respect to

The realist fights back: defending scientific
realism against constructive empiricism
1.   Challenge the observable/unobservable distinction
2.   Acceptance of theory involves a commitment to
     interpret and talk about the world in its terms
3.   The strong form of the underdetermination
     argument applies to both unobservables and
     observables. The constructive empiricist is guilty of
     selective skepticism. The constructive empiricist is
     being inconsistent.

First objection: observable/unobservable

   First objection: no meaningful distinction can be
    drawn between the observable and the
    unobservable. Furthermore, no epistemological
    significance hangs on the distinction.
   The realist’s point is that there is nothing special
    about unobservable entities that prevents us
    knowing about their existence. That is, “nothing is
    unobservable in principle” (Ladyman 188).
   This point was raised by Grover Maxwell in 1962.
Observable/unobservable distinction

   Maxwell: there is a continuum between seeing
    normally, seeing with binoculars, seeing with a
    microscope, seeing with an electron microscope.
    Where is the line between observable and
   van Frassen: vague predicates, like ‘red’, ‘tall’,
    can do epistemological work.
   van Frassen: what we can and cannot know
    coincides with the observable and unobservable.
    Reply to the first objection

   van Fraassen’s aim: skepticism about unobservable.
   Maxwell: nothing is unobservable in principle. This
    means that entities may be observed under the right
    sort of circumstances. Electron microscope, for
   For van Frassen, ‘observable’ is to be understood as
    observable-to-us: “X is observable if there are
    circumstances which are such that, if X is present to us
    under those circumstances, then we observe it” (188).
    Reply to the first objection

   What we can or cannot observe is due to the fact:
    “the human organism is, from the point of view
    of physics, a certain kind of measuring apparatus.
    As such it has certain limitations … it is these
    limitations to which the ‘able’ in ‘observable’
    refers—our limitations qua human beings” (189)

Reply to the first objection

   The ‘us’ refers to the human epistemic
    community. The epistemology is our
   However, if in the future, we encounter other
    beings whose senses are better than ours, and the
    two epistemic communities are integrated, then
    the observable/unobservable boundary shifts
    appropriately. We would be at the sight-impaired
    end of the community
Reply to the first objection

   What then is the difference between the moons of
    Jupiter and positrons?
   Were we in a space ship and were close enough to
    Jupiter, we would observe the moons of Jupiter.
   However, we do not directly observe positrons. We
    infer their existence by the tracks in a cloud chamber.
   There may well be another theory which is empirical
    equivalent but denies that positrons exist—the
    leprechaun theory.

    Reply to the first objection

   The realist may object: “why does van Frassen allow
    change in spatiotemporal location when determining
    what is observable, but not the constitution of our
    sensory organs?”
   van Frassen’s response: we are like beings whose
    only difference is that they are closer to Jupiter, but
    we are not like beings with different sensory organs.
   If we had electron microscopic eyes, we might not
    observe positrons.
Second Objection: Acceptance and belief

   The objection: Acceptance of theory involves a
    commitment to interpret and talk about the world
    in its terms
   The scientific realist challenges van Fraassen’s
    distinction between belief and ‘acceptance’: the
    realist argues that van Fraassen’s position is

    Second objection

   The difference between belief and acceptance
   Does the following statement ‘I believe p (p be any
    statement) but it is not true’, make sense?
   Believing in p implies one is committed to the truth
    of p
   van Frassen claims that ‘I accept p’ does not imply
    that one is committed to the truth of p.
   Is he right?

Reply to second objection:

   Does it make sense to say that ‘I accept p but p is
    not true’? Is there a contradiction in saying ‘I
    accept p but p is not true’?
   Consider the case of Newtonian mechanics
   We accept it for use everyday but we are not
    committed to saying that it is true, which it isn’t
    strictly speaking.

Belief and acceptance:

   The above example illustrates the difference in
    epistemic attitude between believing in and
    accepting a statement, or theory.
   There appears to be no contradiction in accepting
    a theory for use but believe it to be false.
   The realist objection fails.

Third objection: selective skepticism

   In order to appreciate the third objection, we need
    to consider what realists mean by ‘explanation’?
   Realists hold that the truth (or approximate truth)
    of a hypothesis is a necessary condition for it to
    be part of a genuine scientific explanation.
   That is why, for realists, explanations require
    more than empirical adequacy (what is ‘empirical

Scientific explanations

   Realists argue that there are principled ways of
    breaking underdetermination. A rational
    justification can be offered.
   For them, inference to the best explanation (IBE)
    shows that empirical equivalence of theories does
    not imply evidential equivalence.
   Realists use IBE to argue for the existence of
   The constructive empiricist must offer a critique
    of IBE if they are to succeed in arguing their case.

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